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OC e6600: is it ok to adjust CPU multiplier?

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May 23, 2007 8:47:56 PM

I have been reading about overclocking the e6600 and it seems that most people try to overclock the CPU using the 9x multiplier with 1:1 for the memory. I have DDR2 800 memory which corresponds to a 400mHz fsb, but that means trying to achieve a CPU frequency of 3.6 GHz which seems to cause stability problems for many people.

So I was wondering if there is any benefit gained from lowering the CPU multiplier to 8 and running at 3.2 GHz with 400 mHz FSB, rather then 3.2 GHz with fsb of 355 using the 9x multiplier? It seems like an easy way to increase the ram speed while still achieving the same CPU speed? Or am I missing something? Any help would be appreciated, thanks!
May 23, 2007 9:10:34 PM

Should be okay to use the x8 with 400 memory clock speed, for 3.2 ghz

That basically one benefit, using the lower multiplier to achieve a target OC that you want, with a 1:1 ratio.
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a b K Overclocking
May 23, 2007 10:07:10 PM

I just attempted this and it set my machine into a continuous reboot loop.
Should any other settings be changed?
Related resources
May 23, 2007 10:12:16 PM

It's fine to adjust it down. There was an article on hardOCP last summer where that was how they achieved a maximum oc. (Their page ain't loadin or i'd search and leave the link :/  )
May 23, 2007 10:17:43 PM

Thanks grimmy, I'll give it a try with 8x. I guess my basic question was, is a CPU speed of 3.2 GHz with 8x multiplier as fast as 3.2 GHz with 9x?

If so, the 8x has a higher FSB and shound perform better, so why use 9x when it seems to be slowing down the FSB/memory?
May 23, 2007 10:43:05 PM

Quote:
"If so, the 8x has a higher FSB and shound perform better, so why use 9x when it seems to be slowing down the FSB/memory?"


People use 9x multiplier because of the following:
1.they didn't know it can be changed
2. they didn't know how to change it
3. they don't want to change it ( laziness)
4. motherboard problems when changed to 8x multiplier. ( mainly caused by inability of reaching such FSB. )
5. Your computer consumes more energy when the fsb is highier
6. not fast enough ram
May 23, 2007 11:09:06 PM

Quote:
Thanks grimmy, I'll give it a try with 8x. I guess my basic question was, is a CPU speed of 3.2 GHz with 8x multiplier as fast as 3.2 GHz with 9x?

This is debatable. I don't think there is a definitive answer. I'd try both and see how each turns out.
May 23, 2007 11:16:31 PM

Agreed... debatable.

Only thing I recall, the system seems more responsive when you have the 1:1 ratio, from what I've read.

Its been awhile since I read the article.

But basically, a 3.2 ghz OC is still a very nice OC, and a 1:1 ratio helps reduce latencies from what I understand.
May 23, 2007 11:18:04 PM

3.2 ghz at 9x should be a little faster than 8x when comparing its raw speed, but if your ram ratio is at 1:1 ratio, then 3.2ghz at 8x should a little bit faster. It isn't noticeable in most applications thought, only in benchmarks and certain applications that's ram intensive.
May 23, 2007 11:28:15 PM

what about games would there be a big difference in things like loading times.
May 23, 2007 11:38:08 PM

If everything in your system is the same except for the CPU multiplier.. then you can't even notice any improvement in speed during games. It might improve the FPS by 0.0001, but thats useless.
May 24, 2007 12:20:44 AM

Quote:
Thanks grimmy, I'll give it a try with 8x. I guess my basic question was, is a CPU speed of 3.2 GHz with 8x multiplier as fast as 3.2 GHz with 9x?

If so, the 8x has a higher FSB and shound perform better, so why use 9x when it seems to be slowing down the FSB/memory?
They should perform quite similarly. With an 8x multi and 400FSB...depending on your RAM, you'll likely be running 4-4-4-12. With the 9x multi and 355/356FSB...you might be able to tighten the RAM timings a bit, which will help overcome the 8x multi's higher FSB. So basically, if you have a good overclocking board(capable of high FSB's), and good RAM....use the 8x multi. GL :) 
May 24, 2007 12:28:10 AM

Here is a thread that looked into this in more detail. Graysky put together some good data here comparing different FSB's and how it affected performance doing video encoding.

http://forumz.tomshardware.com/modules.php?name=Forums&file=viewtopic&t=224617&highlight=

My own experience was that early on I had stability problem at 350-400 so I settled on 401*8. It turned out I get slightly better performance at 356*9. My guess is that what I lose in memory speed I make up being in a better place with the fsb strap. When picking a FSB speed, your motherboard and how it handles the FSB strap will be a big factor.
May 24, 2007 12:53:25 AM

does anyone by any chance know the FSB straps for P965 chipset? Kind of off topic but oh well.
May 24, 2007 1:08:18 AM

Great.... Thats exactly what i'm looking for including the same mobo too. Thanks
May 24, 2007 1:19:23 AM

After reading it.... It would be great to change to multiplier to 6 or 7 to achieve better FSB. This would yield more performance because of the RAM bandwidth.
May 24, 2007 1:26:13 AM

I just wished i had 1066mhz Ram. and P5B mobo
multiplier at 7 (core2duo e6300 multiplier )

MOBO FSB 533mhz, CPU fsb, 2132, CPu clock speed 3.731 GHz ( possible )
or

MOBO FSB 545mhz, CPU FSB 2180, Cpu clock speed 3.815.ghz
May 24, 2007 2:07:52 AM

Thanks for the links! This clears up a lot.
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May 24, 2007 2:09:29 AM

i have my E6600 @ 400x8 (3200) with DDR2-800 memory - workin solid and sweat
May 24, 2007 2:12:55 AM

Quote:
i have my E6600 @ 400x8 (3200) with DDR2-800 memory


Isn't it suppose to be 400x4? ddr=x2 dual channel =x2

so 400x4 is (1600) with DDR2-800 memory.

Unless you have 4 channel memory controller.
May 24, 2007 2:26:35 AM

Opps.... I didn't read that post carefully. I really need to get a new pair of glasses. ( -0.1, -0.1)
May 24, 2007 5:33:07 AM

Hi there, I'm bit confused. Is not the point to keep the 1:1 ratio? If you happen to get the memory going with let say 450 MHz, it should be better than with 400 MHz? The higher the better or is this 400 MHz some magic number?
May 24, 2007 6:41:35 AM

The faster the speed isn't always better. You have to factoring in the reliability , chipset strap change, errors, power consumption and many others. Usually, higher ram speed at 1:1 ram ratio should yield more performance in benchmarks and few programs. It's usually the best the have the ram ratio at 1:1. You'll only notice significant performance increase of the ram when its speed is increased by 50%~. The performance is limited by the FSB when the ram frequency is highier than the FSB frequency. At 1:1 ram ratio, neither FSB or Ram should limit each other.
May 25, 2007 7:30:02 AM

Sry... My English is unclear.
Quote:
You'll only notice significant performance increase of the ram when its speed is increased by 50%~

restated:
You'll only notice a performance increase of the ram when its speed is significantly increased. e.g setting the RAM divider to 1:2 or 2:3.
!